2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/213222We compute complete tree level matrix elements for $gg , q \bar q \rightarrow b \bar b W^+W^-$. We analyze the irreducible backgrounds to top signal at the Tevatron and at the LHC. Their contribution to the total cross section is about $5 \%$ at the LHC, due to single resonant channels. Several distributions with contributions from signal and backgrounds are presented.13 LaTex pages, 2 figs using feynman.sty, 5 ps figuresHigh Energy Physics - Phenomenologytext